The use of catheter assemblies to view and clear obstructions from various vessels such as coronary arteries is well known in the prior art. Typically, the occlusion must first be located in a manner which preferably minimizes any resultant trauma to the patient from the location procedure. Once located, angioplasty or other methods may be applied to treat the occluded vessel.
In the treatment of occluded blood vessels, ultrasonic energy has been established as a viable means for removing obstructive matter (e.g., atherosclerotic plaque or thromboemboelic material) therefrom. Examples of ultrasonic devices purportedly useable to remove or ablate vascular obstructions are found in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman, et al.), 4,808,153 (Parisi), 4,936,281 (Stasz), 3,565,062 (Kuris), 4,924,863 (Sterzer), 4,870,935 (Don Michael, et al.) 5,069,664 (Suess, et al.) and 4,920,954 (Alliger, et al.), as well as other patent applications including WO87-05739 (Cooper), WO89006515 (Bernstein, et al.), WO90-0130 (Sonic Needle, Corp.), EP316,789 (Don Michael, et al.), DE 3,821,836 (Schubert), DE 2,438,648 (Pohlman) and EP 0443256A1 (Baruch).
In addition to the foregoing, U.S. patent application Ser. No. 07/640,190 entitled ULTRASONIC ANGIOPLASTY DEVICE INCORPORATING IMPROVED TRANSMISSION MEMBER AND ABLATION PROBE, describes an ultrasound catheter device comprising a flexible tubular catheter having a wire-like elongate ultrasound transmission member which extends longitudinally through the catheter. Ultrasonic energy may be passed through the ultrasound transmission member to effect ultrasonic ablation or destruction of unwanted material located adjacent the distal end of the catheter.
Although the disclosure of U.S. patent application Ser. No. 07/640,190 includes certain configurational and/or material modifications intended to constitute an improvement over other prior art ultrasonic devices, there remains a need in the art for further improvements whereby the ultrasound catheter includes an endoscopic visualization apparatus in addition to the ultrasound ablation apparatus. In this respect, though the transmission of ultrasonic energy through the catheter removes obstructive matter from within the blood vessel, the lack of an endoscopic visualization apparatus in prior art ultrasound ablation catheters necessitates the removal of the catheter from within the blood vessel and the subsequent insertion of an endoscope thereinto to visually evaluate the effect of the ultrasound ablation procedure. As will be recognized, the repeated insertion and removal of separate ultrasound ablation and endoscopic visualization catheters into the blood vessel to properly and completely ablate the occlusive material from therewithin is undesirable due to the resultant trauma to the patient. Thus, a catheter device which incorporates combined ultrasound ablation and endoscopic visualization apparatus would provide the advantage of allowing the response of the occlusive material to the ultrasound catheter intervention to be visually evaluated without having to remove the catheter from within the blood vessel. Additionally, the endoscopic visualization apparatus would aid in identifying plaque or other occlusive materials, and would further facilitate the removal of the unwanted material in a more precise fashion by allowing the distal end of the catheter to be properly positioned adjacent the occlusive material. As such, a catheter device incorporating combined ultrasound ablation and endoscopic visualization apparatus would be operable to examine the real internal results of the catheter intervention in a manner minimizing trauma to the patient, and would identify the areas within the blood vessel which require additional intervention to achieve the desired ablation results.